In combustion engines such as, e.g., spark ignition engines and diesel engines for motor vehicles, a mixture of fuel and ambient air is introduced into a combustion chamber, mixed and ignited under controlled conditions and made to burn. This combustion generally occurs incompletely and only approximately 99% of all the components of the mixture are burnt to form water and carbon dioxide. The remaining portion is composed of NOx, CO, soot, tar and hydrocarbons.
In all combustion engines with internal combustion, the gas which is involved changes after each working cycle, that is to say exhaust gas is ejected and fresh gas is fed in. Contemporary motors compress the gas, then the gas is burnt at a high pressure and relaxed again. The maximum possible efficiency depends on the temperature levels at which the combustion heat is fed in and carried away, and therefore on the compression ratio. Incomplete combustion reduces the efficiency further. This also applies to other technical apparatuses with combustion chambers, e.g., to boilers.
Liquid fuels which are based on crude oil contain a large number of different hydrocarbons (hydrogen and bound carbons). In order to convert these fuels into energy, combustion must take place. The result of complete combustion is water and carbon dioxide. If the combustion is not complete, carbon monoxide, soot and tar are produced.
Small and lightweight hydrocarbon molecules such as, e.g., those in gases or petroleum burn easily. In contrast, large and heavy hydrocarbon molecules do not burn as easily and require a relatively high temperature in order to achieve complete combustion. During the combustion process, the speed of the combustion is influenced by the quantity and the concentration of free radicals which are present and are produced by the combustion. These free radicals are generated inter alia by splitting of the hydrocarbon molecules at a relatively high temperature. As result of their high reactivity they react immediately with oxygen. During this oxidation heat is released, which gives rise to further thermal splitting.
If the ignition of the fuel mixture in the combustion chamber of a combustion engine lasts for a relatively long time, the center of combustion also shifts. In addition, a relatively long spark length when there is a relatively consumption of energy can accelerate the wear on the spark plug. An increased concentration of free radicals brings about a more intensive and faster combustion process.
DE 10331418 A9 proposes using a plasma, instead of a spark plug, in order to improve the combustion, and generating of said plasma within the combustion chamber. However, it is problematic to integrate the plasma generator into the combustion chamber and adapt it to the conditions prevailing there.
EP 1845251 A1 discloses a generator with a combustion chamber. A plasma generator or ion generator connected to a high-voltage source generates ions and feeds them into the device at a location which is connected upstream of the combustion chamber, in order to improve the efficiency of the combustion.
JP S58-93952 A discloses a method for improving the efficiency of a combustion engine in which the combustion is promoted by ionized oxygen.
US 2007/0012300 A1 discloses a combustion engine with improved efficiency, in which the combustion is promoted by means of ozone which is enriched in the inflow of air into the combustion chamber.
DE 10358294 A1 discloses a combustion engine having a fuel reformer which, inter alia, may also be embodied as a plasma fuel reformer.